With the United Kingdom looking less united than ever before, a rump Britain could lose influence at the U.N. -- and face mounting pressure to give up its seat on the Security Council.

SOUTHPORT, UNITED KINGDOM - MAY 09: In this photo illustration the flag of the European Union and the Union flag sit on top of a sand castle on a beach on May 09, 2016 in Southport, United Kingdom. The United Kingdom will hold a referendum on June 23, 2016 to decide whether or not to remain a member of the European Union (EU), an economic and political partnership involving 28 European countries which allows members to trade together in a single market and free movement across it's borders for cirtizens. (Photo by illustration by Christopher Furlong/Getty Images)

Post-Brexit Britain may lose Scotland and Northern Ireland, whose voters overwhelmingly favor remaining in the European Union. But they run little risk of losing their seat on the U.N. Security Council, a key source of London’s claim to be a true world power.

That doesn’t mean it will be business as usual for British diplomats at the United Nations. Emotions remain raw over Britain’s Brexit vote, which has roiled global stock markets, sent the value of the pound plummeting to historic lows, and injected an unwelcome degree of uncertainty into world affairs. Over time, European governments are expected to grow less willing to submit to London’s leadership role at the United Nations in crises from Libya to Somalia, where British diplomacy is backed up by European muscle and euros. That will greatly enhance the influence and prestige of France, which will become the sole remaining representative of the European Union, among the council’s big power caucus. Great Britain, meanwhile, may suddenly find itself as “the runt of the Security Council,” quipped Richard Gowan, a U.N. specialist at the European Council on Foreign Relations.

Britain’s departure from the EU is also virtually certain to give new momentum to efforts to change the makeup of the U.N. Security Council, whose five permanent members — the United States, Russia, China, France, and Britain — still reflect the balance of global power at the end of World War II. For two decades, rising powers like Brazil, India, Germany, and Japan have pushed to receive permanent seats of their own. Those efforts have been blocked by regional rivals like Algeria, Argentina, Pakistan, and Italy, which fear for their own standing at the U.N. if their more powerful neighbors make their way onto the world body’s most powerful arm.

“It is difficult to see Brexit doing anything other than making Britain weaker,” said Natalie Samarasinghe, the executive director of the U.K. branch of the United Nations Association. If Scotland and Northern Ireland leave and “we’re left with a rump U.K.,” she said, questions about London’s right to have a Security Council seat “will grow louder.” And while Britain is unlikely to lose its seat, “the pressure will be intense and might inhibit the U.K.’s ability to play what is otherwise a very positive role,” Samarasinghe added.

For the moment, British diplomats are trying to walk the narrow line between stressing that they will abide by the will of their voters while insisting they’ll still find ways of cooperating with allies — and EU members — like France and Germany.

During a closed-door meeting of European Union diplomats Tuesday morning in New York, Britain’s U.N. envoy, Matthew Rycroft, told his European colleagues there was no turning back from the decision to leave the EU. But he sought to assure them that his government would remain engaged on key international matters, and that it would actually intensify its activities on the Security Council, according to several European diplomats. “They say they will stay the course, not diminish their efforts,” said one diplomat.

French, German, Spanish, and other European diplomats told Rycroft that they were shocked by the British decision to withdraw from the EU and that relations would never be the same. At the same time, however, they assured him that they would strive to find ways of collaborating. A senior French official at the meeting told Rycroft that Paris, which holds the other European seat on the Security Council, would continue to closely coordinate its diplomatic activities with Britain, citing a history of “friendship and solidarity.” Though diplomats said that France would probably take on a greater share of responsibilities once Britain leaves the EU.

Rycroft, for his part, told the gathering that Britain would remain a full-fledged member of the European community — with a seat at the table in NATO, the G-7, and the G-20, and a robust military — until its departure is finalized.

Ironically, Rycroft’s assurances that Brexit would have limited impact on Britain’s diplomacy echo claims by proponents of the “Leave” campaign, which issued a statement earlier this year saying that the U.K.’s relationship with the U.N. “would not change significantly if we left the EU. Britain’s permanent seat on the Security Council is central to its ability to play a useful role, and the U.K. will retain it while continuing to support wider reform of the council.”

By contrast, the “Remain” camp, which was led by outgoing Prime Minister David Cameron, warned that Brexit “would disrupt the U.K.’s diplomatic operations” at the United Nations. “The EU brings with it greater scale than the U.K. would have on its own — in diplomatic reach, economic weight and development assistance and other funding,” according to the statement. “Recently, the resolution through diplomatic means of the Iranian nuclear issue counts as a successful case of the U.K.’s bringing EU economic clout in behind its preferred ‘sanctions + negotiations’ policy.”

“The loss of our place inside the EU would make the U.K. a less valuable partner for countries and organizations around the world,” the statement said.

Those concerns were echoed by President Barack Obama, who warned before the vote that Brexit would leave Britain with “less influence in Europe and, as a consequence, less influence globally.” A former senior U.S. diplomat said the departure of Washington’s closest ally in Europe would also lessen America’s influence in the European Union.

For decades, Britain’s influence was derived from its ability to leverage other people’s power — the United States and the European Union — in pursuit of its interests. In Somalia, for example, Britain typically takes the lead in drafting the U.N. resolutions that define international policy. But it’s the wider European Union that foots the bill for African peacekeepers there. In Libya, British diplomats have overseen negotiations on a resolution authorizing the seizure of people smugglers and arms traffickers. While the EU may decide to maintain support for such operations, it is far less likely to want to take its lead from the United Kingdom.

London is the lead policymaker — or penholder — on the council on about a dozen international crises, from Darfur to Libya to Yemen. In recent months, it has returned for the first time in 20 years to U.N. peacekeeping missions, pledging to send more than 250 blue helmets to South Sudan and an additional 70 or so to Somalia. U.N. supporters said they hoped this was the first step in a broader re-engagement in U.N. peacekeeping. But Samarasinghe said Brexit might stall any expansion of a British peacekeeping role. “I don’t think they will pull back” from their commitment, she said. “But I don’t think this is the start of something new, which is what we had previously expected.”